Metamath Proof Explorer


Theorem topnfbey

Description: Nothing seems to be impossible to Prof. Lirpa. After years of intensive research, he managed to find a proof that when given a chance to reach infinity, one could indeed go beyond, thus giving formal soundness to Buzz Lightyear's motto "To infinity... and beyond!" (Contributed by Prof. Loof Lirpa, 1-Apr-2020) (Revised by Thierry Arnoux, 2-Aug-2020) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Assertion topnfbey ⊢ B ∈ 0 … +∞ → +∞ < B

Proof

Step Hyp Ref Expression
1 noel ⊢ ¬ B ∈ ∅
2 pnfxr ⊢ +∞ ∈ ℝ *
3 xrltnr ⊢ +∞ ∈ ℝ * → ¬ +∞ < +∞
4 2 3 ax-mp ⊢ ¬ +∞ < +∞
5 zre ⊢ +∞ ∈ ℤ → +∞ ∈ ℝ
6 ltpnf ⊢ +∞ ∈ ℝ → +∞ < +∞
7 5 6 syl ⊢ +∞ ∈ ℤ → +∞ < +∞
8 4 7 mto ⊢ ¬ +∞ ∈ ℤ
9 8 intnan ⊢ ¬ 0 ∈ ℤ ∧ +∞ ∈ ℤ
10 fzf ⊢ … : ℤ × ℤ ⟶ 𝒫 ℤ
11 10 fdmi ⊢ dom ⁡ … = ℤ × ℤ
12 11 ndmov ⊢ ¬ 0 ∈ ℤ ∧ +∞ ∈ ℤ → 0 … +∞ = ∅
13 9 12 ax-mp ⊢ 0 … +∞ = ∅
14 13 eleq2i ⊢ B ∈ 0 … +∞ ↔ B ∈ ∅
15 1 14 mtbir ⊢ ¬ B ∈ 0 … +∞
16 15 pm2.21i ⊢ B ∈ 0 … +∞ → +∞ < B